dont look at the books, look at the market, ie look at autotrader, cars.com, craigslist, etc and look for similar cars to see what they are listed at, and list accordingly. if you feel your car is better than most, ask more, but be prepared to sit on it; if you feel its average, advertise where similar model, year, equip, mileage cars are listed; if you just want a quick sale, list at a slightly lower price than comparable cars.
whatever your price, have a good reason for it. dont say ït books at¨ explain why youre car is worth it, lower miles, better condition, desirable color combo, more options, service records, etc, and show documentation of recent work, a carfax etc, all these things build value